Method for manufacturing calcium cyanamide



Dec. 26, 1933'. K H|B| METHOD FOR MANUFACTURING CALCIUM CYANAMIDE FiledSept. 21, 1931 i Mom of; vaouoo 1N VEN TOR. XM2/mw mw BY awlw/m ATTORNEYS.

Patented Dec. 2,6, 1933 t f," 1;9j41=1,1772 1 lviE'rHD Fon MANpTAcTURING,GALGIUM Y f :Y 311,5 wml-78) My invention aims' to` provide" anvimproved" methodand apparatus for maufacjtriri'g calciumcyanamide" andanimprovedforiff firoduc't.I `v

More particularly; my invention' relatesitopro-I 5 ducing. small LholldwVbeads o'f calcium' carbide'- havin'g .conductive f surfaces composedsubstantially of carbon; 'and subjectingithese beads atfa properreaction temperatureto theactin of* nil: trogen so Vas tof produce.calcium cya'riar'n'idel i; .An Object' ofr my invention istoprovidealciuml carbide in a formwh'ch may 'be heated and kept` atthe.properfrealctionlteniperature by" any "'suitf'l able means, as 'byexternal. heating; orreferabl! bypassing an4 electric current"throiigllV th nias's'" while itgisbeingsubjected tot the 'action(if/nitro! gen, and thus to eliminate the necessity "d f ex"-l ternalheating meansiheretoforeiretuirediV In the manufacture ofica'lciu'n'icyefnamide; it" has :heretofore been 1 considered? essential t6" 'use govfinely powdered calciuml carbide'. f o'bj ct 'ofY my inventionistoprodcea; granular or hellofviv form of calciumY carbideparticle* aridthereby] eliminate this .Ltroublesom'e` andi Au'ec'orlo'niical'`procedure of crushing'and grinding solid clcium sloping'cnt'airerIZWhich may bprovided' with aV coligjacket' 185` "Thelowr end ofcontainer 12' is openg'f'btrthejsize' of the" opening 'frjay beregulated at will byfmans'ffaadjustahle gate f "Directly 165115111'theVliwer e end off the 'container Vcarbidegtoa iine powder 'beforeAreac'ti1g'thesame Y, 'L

with nitrogen;` A 4 Y 'A further disadvantage. of..prior"procsses` isthat a massive, ha'rd blockff calciumflcyariamid is produced which must"bei crushed and'grund' forlcommercialvlpurposes. M'y process produces;

calcium'l cyanamid in' the? form of', al'srcngy Y porous mass 'whichmay' beJeasily broken flip 'f granules. .Further objects Land resultsofkv my? iriveiition will be apparentifroni the.follwingdsiption" and zthe :accompanying drawing wherein 'I have" shown 'one' embodimentiof myinvention fr'iui''f posesofillustratiom 'j' In the. drawing, r Y Y Fig.vl1 shows an Venlargfed sel'stiinal2V view of the 4 calcium carbideibeadsproducdat anintefme diate' stageofthexprocess';,andi Y if Fig. 24 shows.ai central vertical s''ctio'n of an" apparatusv -for`continuous1f"producing calcium eyanamidefromjawmateriale' j i" AReferringto'sFig.`.2; .azi-electric furnace`4fisfv providedwithY electrodes" 5Aand. bottom' "outlet 6:* Below' the; outlet 6Jis positioned 1"a"sloping` guide Wall??? made cfr ali;refractorymateriahl suc'h' asfirebrick; and'penetrated loyfa.' suitalilnibei of nozzles is; 'direefei'g'utwar'aly 1f Benina-'thief' guide Wall and nozzles is a'cls'd 9itoiiwriicn fisj ncdr'mentedf ffigrss having avalve 11,- '5 .Arranged iinIrOnt f 55. "thefwirnfrsfa a1661111111r'diy`A are goo 'outfintenor 1 and'surface 110 layers 2 of graphite enclosing the calcium carbide 3therein. It Will be apparent that a mass of such beads will conductelectricity and that a current of electricity passed through such a massmay be conveniently utilized for heating the mass uniformly throughout.This is not possible with a mass composed of ordinary calcium carbideparticles owing to the fact that calcium carbide, especially when cold,has such a high electrical resistance as to be classed as an insulatingmaterial rather than a conducting material.

A catalyzer, such as calcium fluoride, calcium chloride, or the like,may be supplied to the jetforming gas and the desirable result obtainedVthat the calcium carbide will simultaneously have a catalytic agentincorporated therein while being formed into beads. This will greatlyassist in the production of calcium cyanamide as hereafter described.

The beads 24 as formed are collected in the container 12 and may becooled down as desired by means of the cooling. jacket 18. Gate 19 isadjusted so that the beads will pass at the desired rate into reactionchamber 13.

When starting operations, the reactiony chamber 13 is allowed to fillwith the beads which will be cold or only Warm. An electric current ispassed through the mass between electrodes 15 and 16. The graphitecoatings ofthe beads form paths for the current and yet possesssufficient resistance to result in the formation of heat. The heat willbe uniformly distributed throughout the mass and may be controlled atwillby varying the amount of current. l y

Ordinary cyanamide reaction chambers require resistance. heatingelements arranged along the wall, sincethe calcium carbide is not itselfan electrical conductor. These heaters are easily damagedand furthermoreheat up the mass slowly and non-uniformly. Electric arc heating requiresa high voltage and is dangerous. These hinderances to successfulvoperation are eliminated by my method. f

When the beads have been heated up to reaction temperature, a stream ofnitrogen gas is directed intotheniass from pipe 14 and reacts with thecalciumicarbide vbeads to form calcium cyanamide. Thisprocess Willbehastened if a catalytic agent has been incorporated into the beads Vasabove described. The reaction heat which results serves to heat up thefresh calcium carbide beads which are supplied fromcontainer 12 .asneeded. Additional heatwhich may be required can be obtained-.bypassinga current between electrodes 15 and 16, and by regulating this currentthe temperature ofthe reacting mass can be controlled and maintained atthe desired point, which is preferably a little above the melting pointof granular calcium cyanamide,k

It will be apparent that the hollowed out beads which I employ cause thereacting mass tobe quite porousrand cause a large surface to be exposedto the nitrogen,` and thus the reaction is greatly hastened andfacilitated.'

The reaction is carried on as a continuous operation, fresh beads beingSupplied at the tcp and calcium cyanamide v1'7 being withdrawn from thebottom of the reaction chamber.-

A further advantage of my method is that the calicum cyanamide isproduced in a very desirable Vform, consisting of'a porous or spongy,loosely conglomerated, mass which'pan be easily sepa'- rated to formgranular cyanamide which, vI believe, has never been obtained prior tomy invention. Such `granular calcium cyanamide has carbon. Bynon-reactive gas is meant a gas which will not react with the calciumcarbide to thedetriment of the process. By catalytic agentf is meant anagent for promoting the reaction between calcium carbide and nitrogen,such as calcium fluoride, calcium chloride, or the like; conductivemeans electrically conductive. By semi-inter-fused is meant inter-fusedto the extent of sticking together but not to the Y extent of preventingmechanical separation.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is: Y' A 1. The method of manufacturing calcium cyanamide,comprising forming Vbeads of calcium car bide having conductive surfacelayers of carbon, collecting the same, raising the temperature lasdesired by passing. an electric current through the mass and subjectingsaid'beads .to gen at a reaction temperature-- Y 2. The methodofmanufacturing granular calcium cyanamide, comprising forming hollowedout beads of calcium carbide having conductive surfaces of carbon,collecting the same, raising the temperature as desired by passing anelectric current through the mass,.and subjecting said beads to gaseous`nitrogen'at a' reaction temperature.

3. The method .of manufacturing granular calcium cyanamide,r comprisingforming beads of calcium carbide mixed with a catalytic agent and -15-beads and passing an electric .current through havingsurface layers ofcarbon, collecting the the mass thereby controlling the temperature asdesired, and subjecting said beads to gaseous nitrogen at a reactiontemperature. Y

4. A continuous process .for manufacturing granular calcium cyanamidefrom basic ma# terialsfcomprising heating amixture of coke and lime Vtoproduce molten calcium carbide, replenishing the cokeA and lime asneeded, passing a stream of the molten materialgin contact withhigh-velocity jets of non-reactive gas to produce hollowed outbeadshaving conductive surface layers of carbon, collecting said beads,raising:

the temperature as desired byy passing an electric current through themass, treating `with' gaseous nitrogen at a reaction temperature nearthe melt--V ing point of calcium cyanamide, and drawing ofi theresulting granular calcium. cyanamide asY formed.

5.A The method specified in claim 4 wherein-the beads have a catalytic:agent embodied therein, especially in the surfaces, asr a -result ofVintroducing said agent into the bead .forming gas..

6. The method of forming beads of calcium carbide having conductivesurfaces'of carbon, comprising directing high-velocity jets of non- 8.vThe method of forming hollowedout beads."

of calcium carbide having conductivesurfaces substantially composed ofcarbon, comprising gaseous `nitroiso v1li@ reactive gasthrough moltencalcium carbide. 7. Thev method of forming hollowed out beads passingathin stream of molten calcium carbide past high-velocity jets ofnon-reactive gas.

9. 'Ihe method of forming calcium carbide beads of the characterdescribed and having a Y posed of carbon.

12. As a new productja hollowed out-calcium carbide bead havingconductive surfaces integral 'I l therewith comprising carbon. j

v 13.y As anew product, calcium cyanamide in the form of a porous masscomprising semi-interfused hollowed out beads and fragments thereof.

14. As a-new product,.a hollowed out calcium cyanamide bead.

15. As a new product, granular calcium cyanamide. of theform resulting.from treating hollowed out beads of Acalcium carbide with at a. reactiontemperature.

' KATSUHARU HrBI.

nitrogen isoY

